An I.S. (individual section) machine has a plurality of identical sections each of which has a blank station which receives one or more gobs of molten glass and forms them into parisons having a threaded opening at the bottom (the finish) and a blow station which receives the parisons and forms them into bottles standing upright with the finish at the top. The blank station includes opposed pairs of blankmold halves and the blow station includes opposed pairs of blowmold halves. Each of these mold halves is carried on an insert which is mounted on an arm or support which is displaceable between open and closed positions.
I.S. machines are sized according to center distances, i.e., the maximum container body diameter. Common I.S. machine center distances are double gob (TG) 41/4" and triple gob (DG) 3". Different containers require different amounts of cooling and accordingly the diameter of the mold will increase (providing more room for vertical cooling passages) with increased demand for cooling. Accordingly a DG 41/4" mold may have a 45/8" or 5.0" band diameter and a DG 5" mold may have 45/8", 51/8" or 6" band diameters. The band of the mold is supported on a suitable circumferential groove defined in the supporting insert.
The one constant has been the location of the face of the mold. As a result, as the band diameter increases, the dimension of the supporting insert must inversely change. This means that each band diameter mold has its dedicated insert and that everytime that a band diameter is changed both the molds and the inserts have to be changed.